I particularly like soft and nicely diffused natural light during most of the photo shoots (unless I decide that hard light is what I need for a particular shoot) and I use windows as light diffusers more and more often.
At every location and photo shoot, I like to firstly look around to see how I can make use of the available light and if there are any natural light-modifiers on the set already (I learned this from Bert Stephani). There can be various 'natural' light modifiers on location, like reflectors (light bouncing from the walls) or light diffusers. The pictures present the effect of the latter type and how a big window as a light diffuser was my best friend in my recent photo shoot.
I noticed a really big window just next to the entrance when shooting at the Malte Restaurant in Brussels (Belgium) recently. Without much thinking I decided to (gently) drop all my light equipment I had with me and to use only the soft natural light from the big window which acted as a huge light diffuser. Unfortunately, you don't see the window on the pictures, but you can clearly see the diffused light and the overall effect.
Believe it or not but I didn't use any additional light sources, reflectors or similar for the shots. I'm particularly happy with the effect that the big window gave me as a light diffuser and it would take quite some time to achieve the same effect and results with artificial light and extra diffusers. That's why I research the environment for natural light and 'natural' light modifiers before shooting on location.
Last but not least, I would like to thank very much the owner of the Malte Restaurant in Brussels for letting us to use their premises for the photo shoot. You should definitely visit the place for the great food and ambient atmosphere, or at least to check out their big window to see how nicely it diffuses the light :)